More than 70 people were killed after a mining tunnel collapsed in southwest Mali, Anadolu Agency reported citing an official.

The accident occurred Friday at a gold mining site in the town of Kobadani in the Kolikouro region, killing more than 70 gold miners, Karim Berthe, an official at the National Geology and Mining Directorate, told reporters in the capital Bamako.

Berthe said an investigation has been launched to establish the cause of the accident.

Reports said an estimated 200 gold prospectors were working in the field when the accident occurred.

The mine is normally closed in the rainy season by the government due to the associated risks, local authorities said.

The Mines Ministry in a statement released earlier Tuesday said “several” people were killed and “deeply regretted” the collapse.

The government extended its condolences to the grieved families and people of Mali.

Mali is Africa's third largest gold producer, with gold contributing about 25% to the national budget. But artisanal miners who ignore safety measures are said to be common, especially among young people in remote areas.